It is important to enhance a light take-out efficiency in increasing a luminous efficiency of a flat display panel such as a plasma display panel, a liquid crystal display panel, etc.
For this purpose, electrodes using transparent conductive films are widely used for such flat display panels. In practical use, however, almost all of the transparent conductive films have high resistance values. Especially, a transparent conductive film itself is difficult to be used for a fine and precise electrode which is patterned in a plasma display panel by a long distance. For this reason, the transparent conductive film is combined in most cases with a low resistive material to lower the electric resistance. In general, such a low resistive material is layered on the transparent conductive film in a plasma display panel, wherein the low resistive material is specified as "bus electrode".
A conventional bus electrode is thin so that it can be formed on a transparent conductive film, wherein the transparent conductive film is deposited on a glass substrate by using tin oxide in the CVD process, and the bus electrode is deposited on the transparent conductive film by using aluminum in a thin film formation process such as the sputter process. The deposited transparent conductive film and bus electrode are covered by a thick dielectric layer of a low melting point glass which is printed in the screen printing process, and then fired.
Practically, however, the bus electrode is preferably as thick as possible, because a thick bus electrode increases the productivity and facilitates a large area.
In this point, a conventional plasma display panel has a disadvantage in that it is difficult to make a bus electrode thick, because a thick bus electrode floats on a printed dielectric layer above a transparent conductive film as a result of erosion of the electric layer between the bus electrode and the transparent conductive film during firing of the printed dielectric layer.